In honeybee （Apis mellifera） colonies, queens and workers are altemative forms of the adult female honeybee that develop from genetically identical zygotes but that depend on differential nourishment. Queens and wor...In honeybee （Apis mellifera） colonies, queens and workers are altemative forms of the adult female honeybee that develop from genetically identical zygotes but that depend on differential nourishment. Queens and workers display distinct morphologies, anatomies and behavior, better known as caste differentiation. Despite some basic insights, the exact mechanism responsible for this phenomenon, especially at the molecular level, remains unclear although some progress has been achieved. In this study, we examined mRNA levels of the TOR （target of rapamycin） and Dnmt3 （DNA methyltransferase 3） genes, closely related to caste differentiation in honeybees. We also investigated mRNA expression of the S6K （similar to RPS6-p70-protein kinase） gene linked closely to organismal growth and development in queen and worker larvae （1-day and 3-day old）. Last, we investigated the methylation status of these three genes in corresponding castes. We found no difference in mRNA expression for the three genes between 1st instar queen and worker larvae; however, 3rd instar queen larvae had a higher level of TOR mRNA than worker larvae. Methylation levels of all three genes were lower in queen larvae than worker larvae but the differences were not statistically significant. These findings provide basic data for broadening our understanding of caste differentiation in female honeybees.展开更多
Nutrition contributes to honey bee caste differentiation,but the role of individual nutrients is still unclear.Most essential amino acid contents,except that of methionine(Met),are greater in royal jelly than worker j...Nutrition contributes to honey bee caste differentiation,but the role of individual nutrients is still unclear.Most essential amino acid contents,except that of methionine(Met),are greater in royal jelly than worker jelly.After〜3.5 i the Met content in the latter was slightly greater than in the former.Met is the major raw material used in the synthesis of S-adenosyl-L-methionine,an active methyl donor for DNA methylation,which is an epigenetic driver of caste differentiation.Here,we tested whether Met regulates caste differentiation in honey bees by determining its effects on the caste development of bees receiving four diets:the basic,basic+0.2%Met,basic+0.2%Met+20 mg/kg 5-azacytidine,and basic+20 mg/kg 5-azacytidine.The presence of Met decreased the adult bee body length and the numbers of ovarioles,indicating that Met may direct the development of female larvae toward worker bees.The upregulated expression of SAMS,Dnmtl,and Dnmt3 caused by Met exposure in 4-d-old larvae indicated that the worker-inductive effects of Met may occur through the promotion of DNA methylation.We investigated the co-effects of Met and glucose on bee development,and found that the effects of an increased glucose level on the number of ovarioles and body length did not strengthen the worker-inductive effects caused by Met.Our results contribute to caste development theory and suggest that Met-as a methyl donor一plays a regulatory,but not decisive,role in caste differentiation.展开更多
Caste differentiation in termites is one of the most conspicuous examples of facultative polyphenism in animals.It is clear that specific cuticular formation occurs in hard exocuticles during caste differentiation.How...Caste differentiation in termites is one of the most conspicuous examples of facultative polyphenism in animals.It is clear that specific cuticular formation occurs in hard exocuticles during caste differentiation.However,the developmental pattern of the soft endocuticle in the differentiation pathways of castes is unknown.To reveal whether the endocuticle is involved in caste differentiation,we compared the exocuticle and endocuticle thickness of individuals in 2 pathways(nymph line and worker line)of caste differentiation in the termite Reticulitermes aculabialis.The endocuticle protein genes were identified by transcriptome analysis and the expression patterns of these genes were confirmed in caste differentiation.We found that the endocuticle structure showed dynamic changes in 2 pathways,and the first difference in endocuticle structure occurred after larvae differentiation bifurcated into workers and nymphs.The thinning of the endocuticle was a significant event from nymphs developing into alates with the thickest exocuticle and thinnest endocuticle.The thickest endocuticle layers were found in the heads of the workers and the ultrastructure of the endocuticle in the heads was more complex than that in the thorax–abdomens.Six endocuticle protein genes were identified and annotated as endocuticle structural glycoproteins SgAbd-2,SgAbd-9,and Abd-5.The expression levels of endocuticle protein genes changed dramatically during caste development and the expression levels in neotenic reproductives(secondary reproductives)were significantly higher than those in alates(primary reproductives).These results reveal the roles of endocuticles in caste differentiation and adaptation to the environment.展开更多
基金supported by the Yunnan Government(2009CI119)Modern Agricultural Industry Technology System(Honeybee)(CARS-45-kxj14)
文摘In honeybee （Apis mellifera） colonies, queens and workers are altemative forms of the adult female honeybee that develop from genetically identical zygotes but that depend on differential nourishment. Queens and workers display distinct morphologies, anatomies and behavior, better known as caste differentiation. Despite some basic insights, the exact mechanism responsible for this phenomenon, especially at the molecular level, remains unclear although some progress has been achieved. In this study, we examined mRNA levels of the TOR （target of rapamycin） and Dnmt3 （DNA methyltransferase 3） genes, closely related to caste differentiation in honeybees. We also investigated mRNA expression of the S6K （similar to RPS6-p70-protein kinase） gene linked closely to organismal growth and development in queen and worker larvae （1-day and 3-day old）. Last, we investigated the methylation status of these three genes in corresponding castes. We found no difference in mRNA expression for the three genes between 1st instar queen and worker larvae; however, 3rd instar queen larvae had a higher level of TOR mRNA than worker larvae. Methylation levels of all three genes were lower in queen larvae than worker larvae but the differences were not statistically significant. These findings provide basic data for broadening our understanding of caste differentiation in female honeybees.
基金Funds of Shandong Province"Double Tops"Program(2016-2020)Shandong Province Agricultural Fine Varieties Breeding Projects(2017LZN006)the earmarked fund for the China Agriculture Research System(No.CARS-44).
文摘Nutrition contributes to honey bee caste differentiation,but the role of individual nutrients is still unclear.Most essential amino acid contents,except that of methionine(Met),are greater in royal jelly than worker jelly.After〜3.5 i the Met content in the latter was slightly greater than in the former.Met is the major raw material used in the synthesis of S-adenosyl-L-methionine,an active methyl donor for DNA methylation,which is an epigenetic driver of caste differentiation.Here,we tested whether Met regulates caste differentiation in honey bees by determining its effects on the caste development of bees receiving four diets:the basic,basic+0.2%Met,basic+0.2%Met+20 mg/kg 5-azacytidine,and basic+20 mg/kg 5-azacytidine.The presence of Met decreased the adult bee body length and the numbers of ovarioles,indicating that Met may direct the development of female larvae toward worker bees.The upregulated expression of SAMS,Dnmtl,and Dnmt3 caused by Met exposure in 4-d-old larvae indicated that the worker-inductive effects of Met may occur through the promotion of DNA methylation.We investigated the co-effects of Met and glucose on bee development,and found that the effects of an increased glucose level on the number of ovarioles and body length did not strengthen the worker-inductive effects caused by Met.Our results contribute to caste development theory and suggest that Met-as a methyl donor一plays a regulatory,but not decisive,role in caste differentiation.
基金supported by the National Natural Science Foundation of China[31870389].
文摘Caste differentiation in termites is one of the most conspicuous examples of facultative polyphenism in animals.It is clear that specific cuticular formation occurs in hard exocuticles during caste differentiation.However,the developmental pattern of the soft endocuticle in the differentiation pathways of castes is unknown.To reveal whether the endocuticle is involved in caste differentiation,we compared the exocuticle and endocuticle thickness of individuals in 2 pathways(nymph line and worker line)of caste differentiation in the termite Reticulitermes aculabialis.The endocuticle protein genes were identified by transcriptome analysis and the expression patterns of these genes were confirmed in caste differentiation.We found that the endocuticle structure showed dynamic changes in 2 pathways,and the first difference in endocuticle structure occurred after larvae differentiation bifurcated into workers and nymphs.The thinning of the endocuticle was a significant event from nymphs developing into alates with the thickest exocuticle and thinnest endocuticle.The thickest endocuticle layers were found in the heads of the workers and the ultrastructure of the endocuticle in the heads was more complex than that in the thorax–abdomens.Six endocuticle protein genes were identified and annotated as endocuticle structural glycoproteins SgAbd-2,SgAbd-9,and Abd-5.The expression levels of endocuticle protein genes changed dramatically during caste development and the expression levels in neotenic reproductives(secondary reproductives)were significantly higher than those in alates(primary reproductives).These results reveal the roles of endocuticles in caste differentiation and adaptation to the environment.
